Use the official SD Memory Card Formatter for the most reliable results on Windows or Mac. 2. Install the R4 Kernel (Firmware)
The most common reason R4 cards fail to load is incorrect formatting.
Connect your microSD card to your PC and format it to FAT32 .
Downloading games to an R4 card is a straightforward process that transforms your Nintendo DS into a versatile multimedia handheld. To get started, you will need a (32GB or smaller is recommended), a USB microSD card reader , and your R4 card . 1. Prepare Your MicroSD Card
An R4 card cannot run games without its "operating system," known as the kernel.
Note: Original R4 cards (non-SDHC) only support cards up to 2GB and may require standard formatting.